The present invention relates to an ink jet recording head unit provided with a plurality of ink flow passages, each being designed to supply ink to nozzle openings through a common ink chamber from an ink supply source, and also relates to an image recording device having the same.
An image recording device such as a printer, a plotter and a facsimile machine is available, which has an ink jet recording head provided with a plurality of ink flow passages each being designed to supply ink to nozzle openings through a common ink chamber from an ink cartridge.
A strong demand exists to miniature the ink jet recording head of this type, and thus the plurality of ink flow passages must be installed in a limited space. For this reason, it is difficult to make uniform the volumes of the common ink chambers.
Of the recording head capable of ejecting ink of plural colors, such a type is available, in which the number of nozzle openings of a black nozzle array frequently used for document print is more than the number of nozzle openings of another chromatic color nozzle array, and the recording head of this type is, in particular, difficult to make the volumes of the common ink chambers uniform.
The volume difference of the common chambers causes variation in flow passage resistance and inertance ink flow passage by ink flow passage, and consequently, ink ejection performance is varied.
Further, an ink cartridge is required to be larger to realize more and more print, and therefore it becomes more difficult to make uniform the length of an ink supply passage (for example, a flow passage from the ink cartridge to the recording head), which constitutes a part of the ink flow passage, causing large variation in ejection performance.
The present invention was made in view of the above circumstances, and an object thereof is to provide a recording head unit and an image recording device, which can prevent problems caused due to a reservoir-to-reservoir volume difference and a flow passage resistance difference.
The present invention is proposed in order to attain the above-noted object, and the invention provides, for instance, the followings:
(1) An ink jet recording head unit comprising: at least one nozzle array in which a plurality of nozzle openings are arrayed; a plurality of common ink chambers, each adapted to store ink to be ejected; compliance parts provided to wall surfaces defining the common ink chambers, respectively; and a plurality of ink flow passages which supply ink from ink supplying sources through the common ink chambers to the nozzle openings, wherein:
of the plurality of the ink flow passages, an ink flow passage longer than another ink flow passage has the compliance part of the common ink chamber, which is located at a middle of the ink flow passage and which is set smaller in comparison to the other ink flow passage.
(2) An ink jet recording head unit comprising: at least one nozzle array in which a plurality of nozzle openings are arrayed; a plurality of common ink chambers, each adapted to store ink to be ejected; compliance parts provided to wall surfaces defining the common ink chambers, respectively; and a plurality of ink flow passages which supply ink from ink supplying sources through the common ink chambers to the nozzle openings, wherein:
of the plurality of the ink flow passages, an ink flow passage smaller in flow passage resistance than another ink flow passage has the compliance part of the common ink chamber, which is located at a middle of the ink flow passage and which is set smaller in comparison to the other ink flow passage.
(3) An ink jet recording head unit comprising: at least one nozzle array in which a plurality of nozzle openings are arrayed; a plurality of common ink chambers, each adapted to store ink to be ejected; compliance parts provided to wall surfaces defining the common ink chambers, respectively; and a plurality of ink flow passages which supply ink from ink supplying sources through the common ink chambers to the nozzle openings, wherein:
of the plurality of the ink flow passages, an ink flow passage smaller in inertance than another ink flow passage has the compliance part of the common ink chamber, which is located at a middle of the ink flow passage and which is set smaller in comparison to the other ink flow passage.
(4) The ink jet recording head unit according to any of (1) to (3), wherein the nozzle array is divided into a plurality of nozzle blocks, and each of the nozzle blocks is communicated with a respective one of the common ink chambers, so that ink can be supplied block by block.
(5) The ink jet recording head unit according to (4), wherein the nozzle array is divided into three of the nozzle blocks, three of the common ink chambers are formed for the nozzle array, and ink of three kinds can be ejected from the single nozzle array.
(6) An image recording device including the inkjet recording head unit defined in any of (1) to (5).
The present disclosure relates to the subject matter contained in Japanese patent application Nos. 2000-157884 (filed on May 29, 2000), and 2001-140832 (filed on May 11, 2001), which are expressly incorporated herein by reference in their entireties.